Estimating Fine-Root Production and Mortality in the Biomass Plantations

Abstract

Loblolly pine (Pinus taeda L.), silver maple (Acer saccharinum L.), and cottonwood (Populus deltoides Bartr.) are short-rotation woody crops with potential use for biomass plantations. The study of fine-root production and mortality in these intensively managed crops is important to understand carbon and nutrient cycling in these systems. We used minirhizotrons to measure monthly fine-root production and mortality of each species in a biomass plantation during the second growing season in Collins, Arkansas, USA. Images were taken and digitized on a monthly basis from March 2008 to February 2009 to calculate volumes and were converted into dry-weight biomass. Data analysis showed that net fine-root production varied among the species and the time of year. Loblolly pine had significantly greater net fine-root production and mortality than others. Overall fine-root production was greatest during fall months, whereas fine-root mortality showed no seasonal difference.

Keywords:

• Cottonwood
• fine roots
• loblolly pine
• minirhizotrons
• silver maple

Acknowledgment

The study was supported by University of Arkansas−Monticello, USA. The authors thank Hal O. Liechty, Robert L. Ficklin, and Todd M. Fearer for valuable suggestions during the study. Similarly, we thank Bikash Bhandari, Omkar Joshi, and William McCarthy for their field support.